1 NCF (2r)-2-{(1r)-2-oxo-1-[(2-thienylacetyl)amino]ethyl}-5,6-dihydro-2h-1,3-thiazine-4-carboxylic acid 1.000 2 KCP 2-[carboxy-(2-thiophen-2-yl-acetylamino)-methyl]-5-methyl-3,6-dihydro-2h-[1,3]thiazine-4-carboxylic acid 0.957 3 THN 2-[carboxy-(2-thiophen-2-yl-acetylamino)-methyl]-5-methylene-5,6-dihydro-2h-[1,3]thiazine-4-carboxylic acid 0.957 4 63V (2s)-5-methylidene-2-{(1r)-2-oxo-1-[(thiophen-2-ylacetyl)amino]ethyl}-5,6-dihydro-2h-1,3-thiazine-4-carboxylic acid 0.913 5 CED 5-methyl-2-[2-oxo-1-(2-thiophen-2-yl-acetylamino)-ethyl]-3,6-dihydro-2h-[1,3]thiazine-4-carboxylic acid 0.913 6 CEO 5-methylene-2-[2-oxo-1-(2-thiophen-2-yl-acetylamino)-ethyl]-5,6-dihydro-2h-[1,3]thiazine-4-carboxylic acid 0.913 7 1S7 (2r)-2-{(1s)-1-methoxy-2-oxo-1-[(thiophen-2-ylacetyl)amino]ethyl}-5-methylidene-5,6-dihydro-2h-1,3-thiazine-4-carboxylic acid 0.840 8 3S3 (1r)-2-({(R)-carboxy[(2r,5s)-4-carboxy-5-methyl-5,6-dihydro-2h-1,3-thiazin-2-yl]methyl}amino)-2-oxo-1-phenylethanaminium 0.808 9 Q53 (R)-2-((R)-((R)-2-amino-2-phenylacetamido)(carboxy)methyl)-5-methyl-3,6-dihydro-2h-1,3-thiazine-4-carboxylic acid 0.808 10 Q6R (R)-2-((R)-((R)-2-amino-2-phenylacetamido)(carboxy)methyl)-5-chloro-3,6-dihydro-2h-1,3-thiazine-4-carboxylic acid 0.808 11 CD6 (2r)-5-methylidene-2-{(1r)-2-oxo-1-[(phenylacetyl)amino]ethyl}-5,6-dihydro-2h-1,3-thiazine-4-carboxylic acid 0.800 12 9EP (2r)-5-[(acetyloxy)methyl]-2-{(1r)-2-oxo-1-[(thiophen-2-ylacetyl)amino]ethyl}-3,6-dihydro-2h-1,3-thiazine-4-carboxylic acid 0.778 13 CEP Cephalothin group 0.778 14 CES 2-[carboxy-(2-furan-2-yl-2-methoxyimino-acetylamino)-methyl]-5-methyl-3,6-dihydro-2h-[1,3]thiazine-4-carboxylic acid 0.778 15 63U (2s)-2-[(1r)-1-{[(2r)-2-amino-2-phenylacetyl]amino}-2-oxoethyl]-5-methyl-3,6-dihydro-2h-1,3-thiazine-4-carboxylic acid 0.769 16 JNX (2~{R},5~{S})-5-(aminocarbonyloxymethyl)-2-[(1~{S})-1-methoxy-2-oxidanyl-2-oxidanylidene-1-(2-thiophen-2-ylethanoylamino)ethyl]-5,6-dihydro-2~{H}-1,3-thiazine-4-carboxylic acid 0.759 17 1QL (2r)-5-[(carbamoyloxy)methyl]-2-{(1s)-1-methoxy-2-oxo-1-[(thiophen-2-ylacetyl)amino]ethyl}-3,6-dihydro-2h-1,3-thiazine-4-carboxylic acid 0.724 18 LOR Loracabef (open form) 0.704 19 PNK (2r,4s)-2-{(R)-carboxy[(phenylacetyl)amino]methyl}-5,5-dimethyl-1,3-thiazolidine-4-carboxylic acid 0.704